Pharmacologic studies of Barlow and Ing1 and of Paton and Zaimis2 on a series of polymethylene bistrimethylammonium salts revealed that the decane (C10) derivative paralyzes transmission at the neuromuscular junction while the pentane (C5) and hexane (C6) derivatives paralyze transmission at the ganglionic synapse. As a result of these studies, the decane derivative (decamethonium) has been introduced clinically as a curarizing agent while pentamethonium and hexamethonium, the C5 and C6 derivatives, respectively, are undergoing extensive clinical trials as agents for the treatment of hypertension.
Arnold and his associates3 demonstrated with the aid of the optical digital plethysmograph that intravenous injection of pentamethonium iodide in normal persons causes peripheral vasodilatation. The dilatation begins within a minute of injection and persists for at least an hour. Injection of the drug in normal persons, according to Arnold and Rosenheim,4 caused little if any change